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What we don't understand about ion acceleration flares
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Tylka, A. J. Reames, Donald V. Ng, C. K. |
| Copyright Year | 1999 |
| Description | There are now strong associations between the (3)He-rich, Fe-rich ions in "impulsive" solar energetic particle (SEP) events and the similar abundances derived from gamma-ray lines from flares. Compact flares, where wave energy can predominate, are ideal sites for the study of wave-particle physics. Yet there are nagging questions about the magnetic geometry, the relation between ions that escape and those that interact, and the relative roles of cascading Alfven waves and the EMIC waves required to enhance He-3. There are also questions about the relative timing of ion and electron acceleration and of heating; these relate to the variation of ionization states before and during acceleration and during transport out of the corona. We can construct a model that addresses many of these issues, but problems do remain. Our greatest lack is realistic theoretical simulations of element abundances, spectra, and their variations. By contrast, we now have a much better idea of the acceleration at CME-driven shock waves in the rare but large "gradual" SEP events, largely because of their slow temporal evolution and great spatial extent. |
| File Size | 631387 |
| Page Count | 14 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20000034234 |
| Archival Resource Key | ark:/13960/t00052w62 |
| Language | English |
| Publisher Date | 1999-01-01 |
| Access Restriction | Open |
| Subject Keyword | Solar Physics Solar Flares Coronal Mass Ejection Ions Iron Electron Acceleration Energetic Particles Gamma Rays Shock Waves Magnetohydrodynamic Waves Emission Spectra Helium Isotopes Line Spectra Plasma Waves Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
